Interview Question: Check if a number is a palindrome

Given an integer, write code to check if it is a palindrome or not. For example: 24342 is a palindrome but 32767 is not a palindrome.

The signature of the function may be as shown below:

/** Function returns 1 is num is palindrome and returns 0 otherwise.
 */
int checkPalindrome(int num);

Algorithm:

1. First keep the modulus(absolute value) of the number. This is to make the code work for -ve integers also.
2. Reverse the digits of the number and store it in another integer.
3. Compare the two int (original & reversed). If they are equal, return 1, else 0.

Code:

int checkPalindrome(int num)
{
   int rev=0; // To store the reversed num
  
   // Taking the absolute value
   if(num < 0)
      num = -num;
  
   // because n will change while reversing it
   int n = num;
   while(n > 0)
   {
      rev *= 10;
      rev = rev + n % 10;
      n = n/10;
   }
   
   if(num == rev)
      return 1;
   else
      return 0;
}

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